AP: The Philadelphia Mint is testing a variety of recipes to make coins more cheaply without altering quality, durability, size or appearance.

Evaluations of 29 alloys concluded that none met the ideal list of attributes. The Treasury Department concluded that additional study was needed before it could endorse any changes.

The government has been looking for ways to shave the millions it spends every year to make bills and coins. Congressional auditors recently suggested doing away with dollar bills entirely and replacing them with dollar coins, which they concluded could save taxpayers $4.4 billion over three decades.